Rotating washing machines
Western-modern style of washing machines, alternative rotation and horizontal axis, is efficient, but hard to build in a DIY process, because of the cost of the technologies, the difficulties with vibrations ( wet clothes are heavy), the necessity to have slow rotation with heavy clothes. This gives a lot of complexity = cost and necessitate very good materials. http://en.wikipedia.org/wiki/Washing_machine
If you want do design alternative systems with rotation, don’t forget to reverse the rotation after few slow turns, or you will have a ball of dirty clothes… The container must also have some special shape to break this “ball” effect.
Of course, in rich countries, washing machines are quite easy to recycle, and rebuilt with second hand parts, with DIY programmers, mecanical or electronical very easy to do.